At the time it said the hospital followed a "strict regime of continual chemical dosing, thermal disinfections and comprehensive monitoring of the extensive water distribution system".

BBC: Legionella bacteria

The team will be monitoring the reserve at night with special infra-red and thermal imaging cameras, exploring the undergrowth with macro cameras and capturing things the human can't see with special slow motion cameras.

BBC: Springwatch returns to Ynys-hir reserve in mid Wales